It's interesting that your experience is so similar to mine. I truly did expect to see a difference and was surprised I didn't.

I'm sure there are pictures which would reveal these large differences in pixel count. Pictures filled with fine detail—a wall filled with posters, a tree filled landscape, close ups of a butterfly's wings. But I take very few pictures like those. And I suspect most people also take pictures that don't easily reveal such differences in resolution.

I suppose the bottom line to all discussions about number of pixels is "Stop worrying about pixels! Refine your seeing. Work at developing yourself as a photographer. Let your pictures today be better than your pictures yesterday." That is the attitude I try to cultivate for myself.